As set forth in U.S. Pat. No. 5,460,411, a major problem on the nation's highways in the spray caused by rotating tires of truck-trailer transport and like freight carriers that move a majority of cargo and commodities from one point to another. Initial research was directed to controlling the spray cast from the rotating tires. U.S. Pat. No. 5,460,411 discloses that in addition to controlling the spray, a properly designed fender could additionally cool the tires to ensure a longer life and also cool associated brake assemblies to provide for more effective braking.
Tractor trailers, including the spatial relationship between the wheels and the carriages which they support, assume many configurations. There are dry box trailers (vans) which assume a spatial relationship between the loaded carriage and the rotating tires wherein the loaded carriage may only be three to four inches above the top of the rotating tires. There are flat bed trailers which assume a spatial relationship between a loaded carriage and the rotating tires wherein there is substantial clearance between the underside of the loaded carriage and the top of the rotating tire. There are moving vans (trailers) where typically the tires rotate within a wheel well formed within the carriage of the van or buses. There are also trailers which are, in essence, tanks supported on a carrier for transporting gas, oil, etc. Because of all these various combinations, the invention disclosed in the aforementioned patent has varying degrees of effectiveness. For example, when a fender is installed it may be so closely adjacent to the carriage or other structure of the trailer that the air entering the front of the fender is less than what the fender is designed for. This is particularly true for those tractors which now use a side panel called a fuel tank skirt. The skirt used for aerodynamic reasons causes the tires and associated brake assemblies to overheat because of lack of air. The skirt deflects the air away from the tires. Many companies remove the last section of the skirt to get more air onto the tires.
Accordingly, the present invention is directed to an air duct which in one embodiment displaces a portion of the skirt and broadly funnels or directs air up and into the face of an air fender or rotating tire.
In the preferred embodiment of the invention, the air duct is used in combination with an air fender, such as described in the aforementioned patent.
The air duct comprises a depending wall having an upper edge and a bottom edge. Formed within the wall is a leading tunnel section having a discharge end in communication with a following baffle section. Extending from the upper end of the wall is a tread. The tunnel section defines at least one flow path which channels air into the baffle section. The baffle section is defined as being between the discharge end of the tunnel and either the leading surfaces of an air fender or where there is no air fender, the leading surfaces of the associated tire. Air flows through the tunnel and baffle sections of the air duct and is subsequently directed up and into the face of an air fender or rotating tire.
In a particularly preferred embodiment, the baffle section is defined, in part, by a concave surface which directs the air discharged from the tunnels up and onto the central portion of the leading portion of the fender.